Not entirely sure, but it sounds like those two guys have been in the competitive esports scene for a while and got their pride shattered by the 17 year old newcomer. I don't think they were angry just because they lost to a girl but also the fact how she was new to the scene and dominated them with ease. Its like working at a company for 5 years and then suddenly a new, comparable employee fresh out of college is put in a higher position than you after working in the same job and for a lot less time. Gotta give them credit though for giving their word and quiting, most people wouldn't do the same.